Arthrofibrosis after TKA - Influence factors on the absolute flexion and gain in flexion after manipulation under anaesthesia

BACKGROUND Stiffness with decreased range of motion (ROM) has been described as a frustrating complication after TKA. If all methods of physiotherapeutic treatment have been exhausted trying to develop ROM, manipulation under anaesthesia (MUA) can be discussed. The aim of the present study was to show the effect of MUA and to determine the influence of BMI, number of previous surgical procedures, pre-MUA ROM and timing of MUA for the results after MUA in regard to absolute flexion and gain in flexion. METHODS 858 patients underwent TKA at our institution between 2004 and 2009. 39 of these patients underwent MUA because of postoperative knee stiffness. The data were retrospective analysed for the influence of BMI, pre-MUA flexion (/≤ 30 days after TKA) and number of previous surgery on the results after MUA (absolute Flexion/gain in flexion). RESULTS The prevalence for stiffness after TKA was 4.54%. There was a statistically significant improvement in flexion not only directly after MUA but also 6 weeks after MUA. Patients with two or more previous operations before TKA showed statistically significant worse results six weeks after MUA in absolute flexion and gain in flexion(p = 0.039) than patients with one or two previous operations. No statistical significance in absolute flexion (p = 0.655) and gain in flexion (p = 0.328) after MUA between "early" and "late" was detected. The stiffer knees with a flexion below 70° showed significantly worse results (p = 0.044) in absolute flexion six weeks after MUA, but they also had statistical statistically better results with regard to gain in flexion (p ≤ 0.001). CONCLUSION MUA is a good instrument for improving ROM after TKA. The time between TKA and MUA seems less important, so different types of physiotherapeutic treatment could be tried before the procedure is started. MUA in patients with many previous operations and a flexion of less than 70° before MUA is not as effective as in other patients, but they also benefit from MUA.